WHEN LAURIE Adelson and Arthur Tracht set out for the highlands of Bolivia seven years ago, Adelson had no idea they would rediscover an art form that had long been overlooked.

"We were walking with backpacks, hitching rides on the backs of trucks, traveling between Indian villages doing research on Bolivian textiles," she recalls. "We started seeing textiles that looked very different and started to realize they were much older than the pieces we knew. Some of them were absolutely fabulous, but only the Indians realized they existed. Three years ago, we decided we wanted to show these textiles."

That exhibit, "Aymara Weavings: Ceremonial Textiles of Colonial and 19th-Century Bolivia," premiered this month at the Textile Museum. The exhibit was gathered from several private collections, and museum director Patricia Fiske believes it is the first public display devoted solely to the work of the Aymara, a group that inhabits the region around Lake Titicaca in the high plateau of northern Bolivia, Chile and Peru. The accompanying catalogue, written by Adelson and Tracht, is also the first scholarly treatment of the subject.

It was this obscurity that initially fascinated Adelson. She points out that "pre-Columbian textiles have been researched and appreciated, but there was an enormous gap between them and the 20th century. Our goal was to establish continuity by filling that gap."

Adelson and Tracht are outsiders trying to revive the cultural pride that was shattered by intruders during the period of Incan domination and again during the Spanish conquests. Because of poor treatment by the Spanish and their descendants, the Aymara were reluctant to share their textiles with Adelson and Tracht. To the Indians, textiles traditionally have been more precious even than gold as a form of cultural expression. Although everyday articles were used until they fell apart, carefully preserved ceremonial pieces were passed from one generation to the next and used only on important occasions.

Today, there are strong pressures against this proud tradition. "Once, an Indian came to me and tried to sell me a poncho," Adelson recalls. When he modeled the hand-woven poncho, she thought it was perfect for him and told him he should keep it. "I don't wear them," he explained, "because when I come to the city people laugh at me."

Because of this sort of ridicule, many Indians who no longer wish to identify with their cultural heritage attach prestige to machine-made clothing. Adelson has found old textiles that were sewn into potato sacks and gnawed by rats. Piecing together the puzzle of Aymara culture and art has been a slow process, for as Adelson says, "We've been thrilled with our progress, but we still have a long way to go."

A visit to the exhibit immediately explains Adelson's persistence. Because of the quality of the wool and the Aymaras' technical skill, the old textiles have remained fresh and beautiful. The tunics, ponchos, mantles, skirts, bags and belts on display indicate the warp-patterning techniques and well-balanced striped designs the Indians inherited from their pre-Columbian ancestors. Most striking, however, are the textiles' vivid colors. The Aymaras' natural dye technology produced an extraordinary spectrum of brilliant pinks, blues, greens, muted browns and strong dark tones.

Modern Aymara weavings have not retained their former splendor. But if increased public awareness could bring about a renaissance in native Bolivian weaving, this exhibit should help. Under the auspices of the Smithsonian Institution Traveling Exhibition Service, the exhibit will be touring the country for the next two years. The Textile Museum, where Adelson and Tracht will lecture on Aymara male garments on Wednesday, will have the exhibit until Oct. 9.

Adelson is pleased with the reception the exhibit has received here, but fears for Indians like the trader who tried to sell her his poncho. Among Bolivians, she says, "there is no real recognition of the Indians' achievements--or even that they are human."

"Bolivians don't realize that there is prejudice in their country," Adelson sighs. "But it's so bad, they don't see it. And that's why the weavings have never been seen."